"Opa, a new opensource programming language aiming to make web development transparent has been publicly launched. Opa automatically generates client-side Javascript and handles communication and session control. The ultimate goal of this project is to allow writing distributed web applications using a single programming language to code application logics, database queries and user interfaces. Among existing applications already developed in Opa, some are worth a look. Best place to start is the project homepage which contains extensive documentation while the code of the technology is on GitHub. A programming challenge ends October 17th." This is weird. 'Opa' is the nickname my friends gave me 6 years ago. It's still used more often than my actual name...

The language REBOL allows similar use in both client and server side applications.

There are big advantages to this as applications become much smaller and cleaner. My own website has no HTML source and so is described in about 50% less code than would normally be used and I can stay entirely within the mindset of REBOL.

But OPA doesn't seem to get rid of HTML, as far as I can tell in the source for the various examples on github.

Perhaps OPA is too stringently designed to be specifically used for this purpose by simply mashing these parts into the language, and it's not pretty.